Pohl H, Do T P, García-Azorín D, Hansen J M, Kristoffersen E S, Nelson SE, Obermann M, Sandor PS, Schankin CJ, Winther Schytz H, Sinclair A, Schoonman GG, Gantenbein AR
The aim of this study was to collect and rate Green Flags, that is, symptoms or pieces of information indicating that a patient is more likely to suffer from a primary than from a secondary headache.